Trash compactors are useful because they reduce the frequency that a particular trash collection unit needs to be emptied and they reduce the overall volume of trash collected. For example, in restaurant dining rooms, the principle components of the waste are napkins, sandwich wrappers, paper cups and food waste. In a typical fast food restaurant, patrons can fill a trash container with these low density item quickly. The trash container, filled with low density waste, needs to be emptied by an employee more frequently and such trash fills up a dumpster or other collection unit more rapidly. In contrast, a dining room trash compaction unit is filled up by patrons over a longer period of time and produces a higher-density waste. Thus, trash compaction units need to be emptied by employees less often and a single dumpster can hold more waste. This reduces costs.
Most trash compactors share a basic design; a horizontal platen is pressed downwards to compress trash into a receptacle at the bottom of the trash compactor. One point of difference among trash compactor designs is in the mechanism used to actuate the platen. For example, in U.S. Pat. No. 6,367,377 to Gawley et al., a scissors-type mechanism is operated by a horizontal screw actuator. One set of feet are connected to the platen and another set of feet slide in a pair of tracks or on a rack-and pinion of the platen. As the platen is forced downward to compress the trash, the screw experiences ever increasing bending moments and the forces from the scissors mechanism on the platen are applied in an increasingly asymmetric manner. The parts of the mechanism need to be beefier to compensate for this disposition of forces. Further, there is a chance that debris might become lodged between the sliding feet and the rack-and-pinion mechanism in the platen, which would jam the mechanism. Another typical prior art design is found in U.S. Pat. No. 4,100,850 to Wolbrink et al., where the electric motor powering the compacting mechanism moves up and down with the compacting mechanism. This type of design puts undue stress on the electrical leads as they flex to follow the motor through the compaction cycle and the platen does not follow a perfectly vertical path. U.S. Pat. No. 4,024,806 to Weeks et al. describes a trash compactor that requires two vertical screws to drive the compacting mechanism and stabilize the platen.
What is desirable is for further trash compactor designs that reduce the chance of contaminating the compacting mechanism with trash, increase reliability and safety, and reduce cost.